Interactions of diet, exercise, metabolism, and weight change in humans

National Institute Of Diabetes And Digestive And Kidney Diseases

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Abstract

We previously conducted a 4-week inpatient random order crossover study to investigate whether people eat more calories when exposed to a diet with >80% of calories from ultra-processed food (UPF) compared with a diet composed of unprocessed foods with zero UPFs (NCT03407053). The two test diets were matched for daily presented calories, sodium, sugar, fat, fiber, and macronutrients. Study participants were instructed to eat as much or as little as they wanted. We found that participants consumed 500 kcal/d more during the ultra-processed diet period resulting in weight gain and body fat accumulation whereas the participants lost weight and body fat during the unprocessed diet period. These results suggest that UPFs cause excess energy intake and weight gain, although the mechanisms remain uncertain. To investigate the potential roles of non-beverage energy density and hyper-palatable foods in determining increased ad libitum energy intake of diets high in UPFs, we will study 36 adult men and women to investigate the differences in mean daily ad libitum energy intake resulting from consuming four test diets, each for a 1-week period in a randomized, crossover design (NCT05290064). Two of the test diets are similar to those used in our previous study, where the unprocessed diet was low in both non-beverage energy density and hyper-palatable foods, whereas the high UPF diet was high in both of these variables. Two reformulated high UPF diets have been designed, one that is low in both non-beverage energy density and hyper-palatable foods and the other is high in non-beverage energy density but low in hyper-palatable foods. All four test diets are matched for daily presented energy, macronutrients, sugar, and fiber. By comparing mean daily ad libitum energy intake between the four test diets, this study will elucidate the relative contributions of non-beverage energy density and hyper-palatable foods to excess energy intake in high UPF diets.